Turnbull government minister Michaelia Cash was forced to withdraw comments – branded "disgraceful and sexist" – in which she threatened to spread rumours about young women in Opposition Leader Bill Shorten's office.

Just two weeks after Prime Minister Malcolm Turnbull called for cultural change in the way women are treated in Parliament House, Labor's Penny Wong accused Senator Cash of an "outrageous slur" on female staffers.

The Minister for Jobs and Innovation made the comments during a heated Senate estimates exchange with Labor's Doug Cameron on Wednesday, giving public glimpse at the growing tensions between the government and opposition over politician's personal lives in the wake of the Barnaby Joyce scandal.

Mr Joyce's extramarital affair prompted Prime Minister Malcolm Turnbull to ban sexual relations between ministers and their direct reports. The crackdown has given new life to rumours about sex between MPs, or MPs and their staff, creating a toxic atmosphere of rumour and innuendo in Parliament House.

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The clash was centred around the controversy that rocked Senator Cash's office last year when her media adviser quit after admitting to tipping off the media about a looming police raid on the Australian Workers Union. Senator Cash has since shed a number of other staff members.

At one point, Senator Cameron asked Senator Cash the name of her newly appointed chief of staff.

Minister for Jobs and Innovation Michaelia Cash during an estimates hearing at Parliament House in Canberra.Credit:Alex Ellinghausen

That quickly degenerated into a tense exchange in which Senator Cash began making thinly veiled accusations about Mr Shorten.

"If you want to start discussing staff matters, be very, very careful. Because I'm happy to sit here and name every young woman in Mr Shorten's office over which rumours in this place abound," Senator Cash said.

"Do you want to start naming them and for Mr Shorten to come out and deny any of the rumours that have been circulating in this building now for many, many years? It's a dangerous path to go down."

Illustration: Matt Golding

Senator Cameron called those insinuations "nonsense" and repeatedly told Senator Cash to "take a chill pill".

The committee was suspended for a short time in the ensuing uproar.

A little while later Senator Wong came into the committee to demand Senator Cash retract.

"We had the Prime Minister a week ago giving us a fairly moralising speech, saying we need to make this a better workplace for women," Senator Wong said.

"And the minister representing the Minister for Women comes in here making what can only be described as outrageous slurs about the character of female staff working for the Leader of the Opposition.

"It can't be allowed to stand. I think it's disgraceful and sexist, impugning the character of various staff. I would ask the minister to withdraw."

"The point I was making was rumours circulate in this building. It does not mean they are true," she said.

Senator Wong then threatened to take the issue to the floor of the Senate, prompting Senator Cash to say: "If anyone has been offended by my remarks, I withdraw."

Labor MPs were visibly angered by Senator Cash's attack but the opposition did not pursue the matter in question time. However Labor deputy leader Tanya Plibersek gave a speech in which she excoriated Senator Cash for her "mealy-mouthed, weasel" apology.

"Senator Cash’s comments were ghastly, they were sexist, they were a 1950s-style throwback," she said. "The Prime Minister should make her offer a proper apology to all of the young women she has offended."